noun
unfinished; in progress; half-done
Describes something started but not yet completed; often used with nouns like 仕事, 宿題, or ゲーム.
やりかけの仕事がまだ机の上にある。
The unfinished work is still on the desk.
やりかけのゲームをセーブしてから寝た。
I saved the game in progress and then went to bed.
未完成 is a more formal, Sino-Japanese word for 'incomplete' or 'unfinished', often used for projects, works of art, or systems. やりかけ is casual and concrete, referring to tasks or activities left midway.
途中 means 'on the way' or 'in the middle of' and can be used for both physical journeys and ongoing actions. やりかけ specifically emphasizes that the action was started but not finished, and is often used as a noun modifier.
Compound of the continuative form of やる (to do) and かけ (from 掛ける, indicating an action begun but not completed). The kanji 遣り掛け is rarely used.